code: def test_builder_to_backend_smoke(self, compute_unit, backend, dtype):
      t = np.random.randint(0, 5, (4, 2)).astype(np.float32)
      constant = np.random.randint(0, 5, (4, 2)).astype(dtype)
      input_placeholders = {
          "x": mb.placeholder(shape=t.shape),
      }
      input_values = {"x": t}
  
      def build(x):
          y = mb.const(val=constant)
          y = mb.cast(x=y, dtype="fp32")
          return mb.add(x=x, y=y)
  
      expected_output_types = (4, 2, types.fp32)
      expected_outputs = t + constant.astype(np.float32)
  
      run_compare_builder(
          build,
          input_placeholders,
          input_values,
          expected_output_types,
          expected_outputs,
          compute_unit=compute_unit,
          backend=backend,
      )
  
imports: import itertools
  import numpy
  import pytest
  from coremltools.converters.mil.mil import Builder
  from coremltools.converters.mil.mil import get_new_symbol, types
  from coremltools.converters.mil.mil.ops.tests.iOS14 import backends
  from coremltools.converters.mil.mil.ops.tests.testing_utils import UNK_SYM, construct_inputs_from_placeholders, run_compare_builder
  from coremltools.converters.mil.testing_reqs import compute_units
  from coremltools.converters.mil.testing_utils import random_gen, ssa_fn
label_desc: Use image node_id 1 for calling the TestConst obj's underlying member method code with example usage: obj.test_builder_to_backend_smoke(compute_unit, backend, dtype) and returns: mb